Oral prostacyclin analogs (Beraprost Sodium, and others) have been used in the treatment of peripheral arterial disease (PAD) for several years in Japan. Recent studies have documented benefit from oral Beraprost in the treatment of ischemic ulcers, and claudication, setting the stage for a double-blind, placebo controlled study to evaluate the safety and efficacy of Beraprost therapy in patients with limited walking distance due to PAD.